| /* |
| * Copyright (C) 2017 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include <elf.h> |
| #include <stdint.h> |
| |
| #include <memory> |
| #include <string> |
| |
| #include <7zCrc.h> |
| #include <Xz.h> |
| #include <XzCrc64.h> |
| |
| #include <unwindstack/DwarfSection.h> |
| #include <unwindstack/ElfInterface.h> |
| #include <unwindstack/Log.h> |
| #include <unwindstack/Memory.h> |
| #include <unwindstack/Regs.h> |
| |
| #include "DwarfDebugFrame.h" |
| #include "DwarfEhFrame.h" |
| #include "DwarfEhFrameWithHdr.h" |
| #include "Symbols.h" |
| |
| namespace unwindstack { |
| |
| ElfInterface::~ElfInterface() { |
| for (auto symbol : symbols_) { |
| delete symbol; |
| } |
| } |
| |
| Memory* ElfInterface::CreateGnuDebugdataMemory() { |
| if (gnu_debugdata_offset_ == 0 || gnu_debugdata_size_ == 0) { |
| return nullptr; |
| } |
| |
| // TODO: Only call these initialization functions once. |
| CrcGenerateTable(); |
| Crc64GenerateTable(); |
| |
| std::vector<uint8_t> src(gnu_debugdata_size_); |
| if (!memory_->Read(gnu_debugdata_offset_, src.data(), gnu_debugdata_size_)) { |
| gnu_debugdata_offset_ = 0; |
| gnu_debugdata_size_ = static_cast<uint64_t>(-1); |
| return nullptr; |
| } |
| |
| ISzAlloc alloc; |
| CXzUnpacker state; |
| alloc.Alloc = [](void*, size_t size) { return malloc(size); }; |
| alloc.Free = [](void*, void* ptr) { return free(ptr); }; |
| |
| XzUnpacker_Construct(&state, &alloc); |
| |
| std::unique_ptr<MemoryBuffer> dst(new MemoryBuffer); |
| int return_val; |
| size_t src_offset = 0; |
| size_t dst_offset = 0; |
| ECoderStatus status; |
| dst->Resize(5 * gnu_debugdata_size_); |
| do { |
| size_t src_remaining = src.size() - src_offset; |
| size_t dst_remaining = dst->Size() - dst_offset; |
| if (dst_remaining < 2 * gnu_debugdata_size_) { |
| dst->Resize(dst->Size() + 2 * gnu_debugdata_size_); |
| dst_remaining += 2 * gnu_debugdata_size_; |
| } |
| return_val = XzUnpacker_Code(&state, dst->GetPtr(dst_offset), &dst_remaining, &src[src_offset], |
| &src_remaining, CODER_FINISH_ANY, &status); |
| src_offset += src_remaining; |
| dst_offset += dst_remaining; |
| } while (return_val == SZ_OK && status == CODER_STATUS_NOT_FINISHED); |
| XzUnpacker_Free(&state); |
| if (return_val != SZ_OK || !XzUnpacker_IsStreamWasFinished(&state)) { |
| gnu_debugdata_offset_ = 0; |
| gnu_debugdata_size_ = static_cast<uint64_t>(-1); |
| return nullptr; |
| } |
| |
| // Shrink back down to the exact size. |
| dst->Resize(dst_offset); |
| |
| return dst.release(); |
| } |
| |
| template <typename AddressType> |
| void ElfInterface::InitHeadersWithTemplate() { |
| if (eh_frame_hdr_offset_ != 0) { |
| eh_frame_.reset(new DwarfEhFrameWithHdr<AddressType>(memory_)); |
| if (!eh_frame_->Init(eh_frame_hdr_offset_, eh_frame_hdr_size_)) { |
| // Even if the eh_frame_offset_ is non-zero, do not bother |
| // trying to read that since something has gone wrong. |
| eh_frame_.reset(nullptr); |
| eh_frame_hdr_offset_ = 0; |
| eh_frame_hdr_size_ = static_cast<uint64_t>(-1); |
| } |
| } else if (eh_frame_offset_ != 0) { |
| // If there is a eh_frame section without a eh_frame_hdr section. |
| eh_frame_.reset(new DwarfEhFrame<AddressType>(memory_)); |
| if (!eh_frame_->Init(eh_frame_offset_, eh_frame_size_)) { |
| eh_frame_.reset(nullptr); |
| eh_frame_offset_ = 0; |
| eh_frame_size_ = static_cast<uint64_t>(-1); |
| } |
| } |
| |
| if (debug_frame_offset_ != 0) { |
| debug_frame_.reset(new DwarfDebugFrame<AddressType>(memory_)); |
| if (!debug_frame_->Init(debug_frame_offset_, debug_frame_size_)) { |
| debug_frame_.reset(nullptr); |
| debug_frame_offset_ = 0; |
| debug_frame_size_ = static_cast<uint64_t>(-1); |
| } |
| } |
| } |
| |
| template <typename EhdrType, typename PhdrType, typename ShdrType> |
| bool ElfInterface::ReadAllHeaders(uint64_t* load_bias) { |
| EhdrType ehdr; |
| if (!memory_->Read(0, &ehdr, sizeof(ehdr))) { |
| return false; |
| } |
| |
| if (!ReadProgramHeaders<EhdrType, PhdrType>(ehdr, load_bias)) { |
| return false; |
| } |
| |
| // We could still potentially unwind without the section header |
| // information, so ignore any errors. |
| if (!ReadSectionHeaders<EhdrType, ShdrType>(ehdr)) { |
| log(0, "Malformed section header found, ignoring..."); |
| } |
| return true; |
| } |
| |
| template <typename EhdrType, typename PhdrType> |
| bool ElfInterface::ReadProgramHeaders(const EhdrType& ehdr, uint64_t* load_bias) { |
| uint64_t offset = ehdr.e_phoff; |
| for (size_t i = 0; i < ehdr.e_phnum; i++, offset += ehdr.e_phentsize) { |
| PhdrType phdr; |
| if (!memory_->ReadField(offset, &phdr, &phdr.p_type, sizeof(phdr.p_type))) { |
| return false; |
| } |
| |
| if (HandleType(offset, phdr.p_type, *load_bias)) { |
| continue; |
| } |
| |
| switch (phdr.p_type) { |
| case PT_LOAD: |
| { |
| // Get the flags first, if this isn't an executable header, ignore it. |
| if (!memory_->ReadField(offset, &phdr, &phdr.p_flags, sizeof(phdr.p_flags))) { |
| return false; |
| } |
| if ((phdr.p_flags & PF_X) == 0) { |
| continue; |
| } |
| |
| if (!memory_->ReadField(offset, &phdr, &phdr.p_vaddr, sizeof(phdr.p_vaddr))) { |
| return false; |
| } |
| if (!memory_->ReadField(offset, &phdr, &phdr.p_offset, sizeof(phdr.p_offset))) { |
| return false; |
| } |
| if (!memory_->ReadField(offset, &phdr, &phdr.p_memsz, sizeof(phdr.p_memsz))) { |
| return false; |
| } |
| pt_loads_[phdr.p_offset] = LoadInfo{phdr.p_offset, phdr.p_vaddr, |
| static_cast<size_t>(phdr.p_memsz)}; |
| if (phdr.p_offset == 0) { |
| *load_bias = phdr.p_vaddr; |
| } |
| break; |
| } |
| |
| case PT_GNU_EH_FRAME: |
| if (!memory_->ReadField(offset, &phdr, &phdr.p_offset, sizeof(phdr.p_offset))) { |
| return false; |
| } |
| // This is really the pointer to the .eh_frame_hdr section. |
| eh_frame_hdr_offset_ = phdr.p_offset; |
| if (!memory_->ReadField(offset, &phdr, &phdr.p_memsz, sizeof(phdr.p_memsz))) { |
| return false; |
| } |
| eh_frame_hdr_size_ = phdr.p_memsz; |
| break; |
| |
| case PT_DYNAMIC: |
| if (!memory_->ReadField(offset, &phdr, &phdr.p_offset, sizeof(phdr.p_offset))) { |
| return false; |
| } |
| dynamic_offset_ = phdr.p_offset; |
| if (!memory_->ReadField(offset, &phdr, &phdr.p_memsz, sizeof(phdr.p_memsz))) { |
| return false; |
| } |
| dynamic_size_ = phdr.p_memsz; |
| break; |
| } |
| } |
| return true; |
| } |
| |
| template <typename EhdrType, typename ShdrType> |
| bool ElfInterface::ReadSectionHeaders(const EhdrType& ehdr) { |
| uint64_t offset = ehdr.e_shoff; |
| uint64_t sec_offset = 0; |
| uint64_t sec_size = 0; |
| |
| // Get the location of the section header names. |
| // If something is malformed in the header table data, we aren't going |
| // to terminate, we'll simply ignore this part. |
| ShdrType shdr; |
| if (ehdr.e_shstrndx < ehdr.e_shnum) { |
| uint64_t sh_offset = offset + ehdr.e_shstrndx * ehdr.e_shentsize; |
| if (memory_->ReadField(sh_offset, &shdr, &shdr.sh_offset, sizeof(shdr.sh_offset)) && |
| memory_->ReadField(sh_offset, &shdr, &shdr.sh_size, sizeof(shdr.sh_size))) { |
| sec_offset = shdr.sh_offset; |
| sec_size = shdr.sh_size; |
| } |
| } |
| |
| // Skip the first header, it's always going to be NULL. |
| offset += ehdr.e_shentsize; |
| for (size_t i = 1; i < ehdr.e_shnum; i++, offset += ehdr.e_shentsize) { |
| if (!memory_->ReadField(offset, &shdr, &shdr.sh_type, sizeof(shdr.sh_type))) { |
| return false; |
| } |
| |
| if (shdr.sh_type == SHT_SYMTAB || shdr.sh_type == SHT_DYNSYM) { |
| if (!memory_->Read(offset, &shdr, sizeof(shdr))) { |
| return false; |
| } |
| // Need to go get the information about the section that contains |
| // the string terminated names. |
| ShdrType str_shdr; |
| if (shdr.sh_link >= ehdr.e_shnum) { |
| return false; |
| } |
| uint64_t str_offset = ehdr.e_shoff + shdr.sh_link * ehdr.e_shentsize; |
| if (!memory_->ReadField(str_offset, &str_shdr, &str_shdr.sh_type, sizeof(str_shdr.sh_type))) { |
| return false; |
| } |
| if (str_shdr.sh_type != SHT_STRTAB) { |
| return false; |
| } |
| if (!memory_->ReadField(str_offset, &str_shdr, &str_shdr.sh_offset, |
| sizeof(str_shdr.sh_offset))) { |
| return false; |
| } |
| if (!memory_->ReadField(str_offset, &str_shdr, &str_shdr.sh_size, sizeof(str_shdr.sh_size))) { |
| return false; |
| } |
| symbols_.push_back(new Symbols(shdr.sh_offset, shdr.sh_size, shdr.sh_entsize, |
| str_shdr.sh_offset, str_shdr.sh_size)); |
| } else if (shdr.sh_type == SHT_PROGBITS && sec_size != 0) { |
| // Look for the .debug_frame and .gnu_debugdata. |
| if (!memory_->ReadField(offset, &shdr, &shdr.sh_name, sizeof(shdr.sh_name))) { |
| return false; |
| } |
| if (shdr.sh_name < sec_size) { |
| std::string name; |
| if (memory_->ReadString(sec_offset + shdr.sh_name, &name)) { |
| uint64_t* offset_ptr = nullptr; |
| uint64_t* size_ptr = nullptr; |
| if (name == ".debug_frame") { |
| offset_ptr = &debug_frame_offset_; |
| size_ptr = &debug_frame_size_; |
| } else if (name == ".gnu_debugdata") { |
| offset_ptr = &gnu_debugdata_offset_; |
| size_ptr = &gnu_debugdata_size_; |
| } else if (name == ".eh_frame") { |
| offset_ptr = &eh_frame_offset_; |
| size_ptr = &eh_frame_size_; |
| } else if (eh_frame_hdr_offset_ == 0 && name == ".eh_frame_hdr") { |
| offset_ptr = &eh_frame_hdr_offset_; |
| size_ptr = &eh_frame_hdr_size_; |
| } |
| if (offset_ptr != nullptr && |
| memory_->ReadField(offset, &shdr, &shdr.sh_offset, sizeof(shdr.sh_offset)) && |
| memory_->ReadField(offset, &shdr, &shdr.sh_size, sizeof(shdr.sh_size))) { |
| *offset_ptr = shdr.sh_offset; |
| *size_ptr = shdr.sh_size; |
| } |
| } |
| } |
| } |
| } |
| return true; |
| } |
| |
| template <typename DynType> |
| bool ElfInterface::GetSonameWithTemplate(std::string* soname) { |
| if (soname_type_ == SONAME_INVALID) { |
| return false; |
| } |
| if (soname_type_ == SONAME_VALID) { |
| *soname = soname_; |
| return true; |
| } |
| |
| soname_type_ = SONAME_INVALID; |
| |
| uint64_t soname_offset = 0; |
| uint64_t strtab_offset = 0; |
| uint64_t strtab_size = 0; |
| |
| // Find the soname location from the dynamic headers section. |
| DynType dyn; |
| uint64_t offset = dynamic_offset_; |
| uint64_t max_offset = offset + dynamic_size_; |
| for (uint64_t offset = dynamic_offset_; offset < max_offset; offset += sizeof(DynType)) { |
| if (!memory_->Read(offset, &dyn, sizeof(dyn))) { |
| return false; |
| } |
| |
| if (dyn.d_tag == DT_STRTAB) { |
| strtab_offset = dyn.d_un.d_ptr; |
| } else if (dyn.d_tag == DT_STRSZ) { |
| strtab_size = dyn.d_un.d_val; |
| } else if (dyn.d_tag == DT_SONAME) { |
| soname_offset = dyn.d_un.d_val; |
| } else if (dyn.d_tag == DT_NULL) { |
| break; |
| } |
| } |
| |
| soname_offset += strtab_offset; |
| if (soname_offset >= strtab_offset + strtab_size) { |
| return false; |
| } |
| if (!memory_->ReadString(soname_offset, &soname_)) { |
| return false; |
| } |
| soname_type_ = SONAME_VALID; |
| *soname = soname_; |
| return true; |
| } |
| |
| template <typename SymType> |
| bool ElfInterface::GetFunctionNameWithTemplate(uint64_t addr, uint64_t load_bias, std::string* name, |
| uint64_t* func_offset) { |
| if (symbols_.empty()) { |
| return false; |
| } |
| |
| for (const auto symbol : symbols_) { |
| if (symbol->GetName<SymType>(addr, load_bias, memory_, name, func_offset)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| bool ElfInterface::Step(uint64_t pc, Regs* regs, Memory* process_memory, bool* finished) { |
| // Try the eh_frame first. |
| DwarfSection* eh_frame = eh_frame_.get(); |
| if (eh_frame != nullptr && eh_frame->Step(pc, regs, process_memory, finished)) { |
| return true; |
| } |
| |
| // Try the debug_frame next. |
| DwarfSection* debug_frame = debug_frame_.get(); |
| if (debug_frame != nullptr && debug_frame->Step(pc, regs, process_memory, finished)) { |
| return true; |
| } |
| return false; |
| } |
| |
| // This is an estimation of the size of the elf file using the location |
| // of the section headers and size. This assumes that the section headers |
| // are at the end of the elf file. If the elf has a load bias, the size |
| // will be too large, but this is acceptable. |
| template <typename EhdrType> |
| void ElfInterface::GetMaxSizeWithTemplate(Memory* memory, uint64_t* size) { |
| EhdrType ehdr; |
| if (!memory->Read(0, &ehdr, sizeof(ehdr))) { |
| return; |
| } |
| if (ehdr.e_shnum == 0) { |
| return; |
| } |
| *size = ehdr.e_shoff + ehdr.e_shentsize * ehdr.e_shnum; |
| } |
| |
| // Instantiate all of the needed template functions. |
| template void ElfInterface::InitHeadersWithTemplate<uint32_t>(); |
| template void ElfInterface::InitHeadersWithTemplate<uint64_t>(); |
| |
| template bool ElfInterface::ReadAllHeaders<Elf32_Ehdr, Elf32_Phdr, Elf32_Shdr>(uint64_t*); |
| template bool ElfInterface::ReadAllHeaders<Elf64_Ehdr, Elf64_Phdr, Elf64_Shdr>(uint64_t*); |
| |
| template bool ElfInterface::ReadProgramHeaders<Elf32_Ehdr, Elf32_Phdr>(const Elf32_Ehdr&, uint64_t*); |
| template bool ElfInterface::ReadProgramHeaders<Elf64_Ehdr, Elf64_Phdr>(const Elf64_Ehdr&, uint64_t*); |
| |
| template bool ElfInterface::ReadSectionHeaders<Elf32_Ehdr, Elf32_Shdr>(const Elf32_Ehdr&); |
| template bool ElfInterface::ReadSectionHeaders<Elf64_Ehdr, Elf64_Shdr>(const Elf64_Ehdr&); |
| |
| template bool ElfInterface::GetSonameWithTemplate<Elf32_Dyn>(std::string*); |
| template bool ElfInterface::GetSonameWithTemplate<Elf64_Dyn>(std::string*); |
| |
| template bool ElfInterface::GetFunctionNameWithTemplate<Elf32_Sym>(uint64_t, uint64_t, std::string*, |
| uint64_t*); |
| template bool ElfInterface::GetFunctionNameWithTemplate<Elf64_Sym>(uint64_t, uint64_t, std::string*, |
| uint64_t*); |
| |
| template void ElfInterface::GetMaxSizeWithTemplate<Elf32_Ehdr>(Memory*, uint64_t*); |
| template void ElfInterface::GetMaxSizeWithTemplate<Elf64_Ehdr>(Memory*, uint64_t*); |
| |
| } // namespace unwindstack |